<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>原生JS实现购物车结算功能代码</title>
    <link rel="stylesheet" href="../css/style.css" />
</head>

<body>
    <div class="catbox">
        <table id="cartTable">
            <thead>
                <tr>
                    <th><label>
                            <input class="check-all check" type="checkbox" />&nbsp;&nbsp;全选</label></th>
                    <th>商品</th>
                    <th>单价</th>
                    <th>数量</th>
                    <th>小计</th>
                    <th>操作</th>
                </tr>
            </thead>
            <tbody>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/1.jpg" alt="" /><span>Casio/卡西欧 EX-TR350</span></td>
                    <td class="price">5999.88</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">5999.88</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/2.jpg" alt="" /><span>Canon/佳能 PowerShot SX50 HS</span></td>
                    <td class="price">3888.50</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">3888.50</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/3.jpg" alt="" /><span>Sony/索尼 DSC-WX300</span></td>
                    <td class="price">1428.50</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">1428.50</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
                <tr>
                    <td class="checkbox"><input class="check-one check" type="checkbox" /></td>
                    <td class="goods"><img src="../images/4.jpg" alt="" /><span>Fujifilm/富士 instax mini 25</span></td>
                    <td class="price">640.60</td>
                    <td class="count"><span class="reduce"></span>
                        <input class="count-input" type="text" value="1" />
                        <span class="add">+</span>
                    </td>
                    <td class="subtotal">640.60</td>
                    <td class="operation"><span class="delete">删除</span></td>
                </tr>
            </tbody>
        </table>
        <div class="foot" id="foot">

            <a class="fl" id="deleteAll" href="javascript:;">删除</a>
            <div class="fr closing" onclick="getTotal();">结 算</div>
            <input type="hidden" id="cartTotalPrice" />
            <div class="fr total">合计：￥<span id="priceTotal">0.00</span></div>
            <div class="fr selected" id="selected">已选商品<span id="selectedTotal">0</span>件<span
                    class="arrow up">︽</span><span class="arrow down">︾</span></div>
            <div class="selected-view">
                <div id="selectedViewList" class="clearfix">
                    <div><img src="../images/1.jpg"><span>取消选择</span></div>
                </div>
                <span class="arrow">◆<span>◆</span></span>
            </div>
        </div>
    </div>
</body>
<script>
    // 全选和反选

    // 全选:
    // 点击全选, 所有的单选跟随全选的状态

    // 反选:
    // 每次点击单件商品(单选), 判断所有的商品是否全都选中, 全都选中就反选(全选被选中), 否则就是未选中

    var checkAll = document.getElementsByClassName("check-all")[0];
    var checkOneList = document.getElementsByClassName("check-one");
    var addList = document.getElementsByClassName("add");
    var reduceList = document.getElementsByClassName("reduce");

    // 点击全选, 所有的单选跟随全选的状态
    checkAll.onclick = function () {
        var status = this.checked;  // 获取全选的状态
        console.log(status);

        // 所有的单选跟随全选的状态
        // for (var i = 0; i < checkOneList.length; i++) {
        //     var checkOne = checkOneList[i];
        //     checkOne.checked = status;
        // }


        Array.from(checkOneList).forEach(function (checkOne) {
            checkOne.checked = status;
        })

    }

    // 单选:
    // 每次点击单选, 判断所有的单选是否全都被选中,  全都选中就反选(全选被选中), 否则就是未选中

    for (let i = 0; i < checkOneList.length; i++) {
        let checkOne = checkOneList[i];
        checkOne.onclick = function () {
            // console.log(checkOne, i);

            // 如何判断所有的单选是否全都被选中?
            // (1) 计数法
            // var count = 0;
            // for (var j = 0; j < checkOneList.length; j++) {
            //     var item = checkOneList[j];
            //     if(item.checked){
            //         count++;
            //     }
            // }
            // checkAll.checked = count == checkOneList.length ? true : false;


            // (2) 假设法
            // var flag = true; // 假设全都被选中
            // for (var j = 0; j < checkOneList.length; j++) {
            //     var item = checkOneList[j];
            //     if (!item.checked) {
            //         flag = false;
            //         break;
            //     }
            // }
            // checkAll.checked = flag;
            
            
            // (2.1) 
            var flag = Array.from(checkOneList).every(function(checkOne){
                return checkOne.checked;
            })
            console.log(flag);
            checkAll.checked = flag;



        }
    }

    // 点击 “+”     输入框  数量 加一 
    //             小计更新  =  单价*数量
    //             减号按钮的 “-”  出现
    for(let i = 0;i< addList.length;i++){
        let add = addList[i];
        add.onclick = function(){
            console.log(this,add);

            //a. 输入框  数量 加一 
            var countInput = this.previousElementSibling;
            var num = countInput.value;
            num++;
            countInput.value = num;
            // countInput.value ++;
            console.log(num);

            //b. 小计更新  =  单价*数量
            var priceTd = this.parentElement.previousElementSibling;
            var subtotalTd = this.parentElement.nextElementSibling;
            console.log(priceTd,subtotalTd);

            var price = priceTd.textContent;
            subtotalTd.textContent = (price * num).toFixed(2);

            // c  减号按钮的 “-”  出现
            var reduce = countInput.previousElementSibling;
            reduce.textContent = "-";

        }
    }


    // 点击减号    输入框  数量 减一   （细节要求  数量为1的时候  不再减）
    //            小计更新  =  单价*数量 
    //            减之前  判断  如果数量为1  不能减     return false (结束函数)
    //            减之后  判断  如果数量为1  减号按钮的 “-” 消失 (2切1)
    for(let i = 0;i<reduceList.length;i++){
        let reduce = reduceList[i];
        reduce.onclick = function(){
            console.log(this,reduce);

            // a. 输入框  数量 减一 
            var countInput = next(this);
            var num = countInput.value;
            // c. 减之前判断 如果商品数量为1,不能减
            if(num == 1){
                alert("亲,不能再少了!");
                return false;  // 阻止函数继续向后执行
            }
            
            num--;

            // d. 减之后判断, 如果商品数量为1 (2切换为1), "-"消失
            if(num == 1){
                this.textContent = "";
            }


            countInput.value = num;

            // b. 小计更新  =  单价*数量
            var priceTd = prev(parent(this));
            var subtotalTd = next(parent(this));
            console.log(priceTd,subtotalTd);

            var price = priceTd.textContent;
            subtotalTd.textContent = (price * num).toFixed(2);
        }
    }


    function parent(ele){
        return ele.parentElement;
    }

    function prev(ele){
        return ele.previousElementSibling;
    }

    function next(ele){
        return ele.nextElementSibling;
    }


</script>
</html>